Logging to Local Nonvolatile Storage

Last Updated: October 30, 2012

The Logging to Local Nonvolatile Storage feature enables system logging messages to be saved on an advanced technology attachment flash disk. Messages saved on bootflash or a harddisk persist after a device is rebooted.

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Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites for Logging to Local Nonvolatile Storage

The logging buffered Command Must Be Enabled

Before the Logging to Local Nonvolatile Storage feature can be enabled with the loggingpersistent command, you must enable the logging of messages to an internal buffer with the loggingbuffered command. For additional information, see the "Writing Logging Messages to Bootflash or a Harddisk" section.

Restrictions for Logging to Local Nonvolatile Storage

Available Bootflash or Harddisk Space Constrains the Size and Number of Stored Log Files

The amount of bootflash or harddisk space allocated to system logging messages constrains the number of logging files that can be stored. When the allocation threshold is passed, the oldest log file in the directory is deleted to make room for new system logging messages. To permanently store system logging messages, you must archive them to an external device. For more information, see "Copying Logging Messages to an External Disk" section.

Note

Logging to local nonvolatile storage can use up to 2 GB of storage space.

Information About Logging to Local Nonvolatile Storage

System Logging Messages

System logging messages include error and debug messages generated by application programming interfaces (APIs) on the device. Typically, logging messages are stored in a device's memory buffer; when the buffer is full, older messages are overwritten by new messages. All logging messages are erased from the memory buffer when the device reboots.

Writes logging messages from the memory buffer to the specified directory on the device's bootflash or a harddisk.

Before logging messages are written to a file on the bootflash or harddisk, the Cisco software checks to see if there is sufficient disk space. If not, the oldest file of logging messages (by timestamp) is deleted, and the current file is saved.

The filename format of log files is log_MM:DD:YYYY::hh:mm:ss. For example: log_11:26:2012::01:01:41.

Note

This feature supports only one log file per second due to its filename format, which contains a timestamp suffix down to the seconds level.

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Feature Information for Logging to Local Nonvolatile Storage

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 1

Feature Information for Logging to Local Nonvolatile Storage

Feature Name

Releases

Feature Information

Logging to Local Nonvolatile Storage

Cisco IOS XE Release 2.1

The Logging to Local Nonvolatile Storage feature enables system logging messages to be saved on an advanced technology attachment flash disk. Messages saved on bootflash or a harddisk persist after a device is rebooted.

The following command was introduced or modified: loggingpersistent.

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